Frequent-flier miles have taken me around the world. African safaris, a snorkeling trip on the Great Barrier Reef, a Baltic Sea cruise and treks in the Himalayas have all been possible thanks to airfare paid with miles.

So it was a shock when a group of fellow elite-mileage travelers and I recently went to book flights for a cruise and found that that the "taxes and carrier fees" on the flights we wanted were as costly as the co-pay on an out-of-network medical claim.

The good news: Mileage tickets to Rome via American's One World partnership were available for the mid-summer cruise we'd planned. Bad news: The "taxes and fee" tariff was $700. Buying the ticket outright was only a few hundred dollars more.

American Express miles - which can be applied to Delta's SkyMiles program and SkyTeam members - wouldn't help us either. Seats were available there as well - for a whopping 110,000 miles.

Not exactly, said Tim Winship, who runs the website FrequentFlier.com. The basic strategy I've used throughout the years does still work, he confirmed. I book as far head as possible, call the airline instead of relying on the Internet alone, and keep trying until I can snag something that works. I'm flexible about dates and don't cringe at paying for a night in an airport hotel - a worthwhile trade for an air ticket worth thousands.

But in recent years, many mileage programs have introduced rule changes, tiered award charts and a la carte fees that have shifted the options. Among the wrinkles:

-Taxes and fees: Government-imposed taxes and fees are unavoidable and can be steep, reaching as much as $200 per economy ticket on flights leaving from London's Heathrow Airport.

Other fees vary by airline. For instance, though I was using American's website to book my Rome award tickets, the available flights I was seeing were on British Airways. It and some other foreign carriers have levied "fuel surcharges" - which accounted for the whopping $700 fee on those tickets to Rome.

Countermeasures: Book early enough (330 days in advance typically is your first opportunity) to snag tickets on an airline that doesn't levy the surcharge. Call the airline booking desk directly and often; they can sometimes come up with options you won't see online. And if at first you don't find what you want, keep checking back.

-Upgrades: If you've been flying long enough, you remember the years when you could buy an economy seat and use miles to upgrade to business or first class. Now many programs will charge you those miles PLUS a "co-pay" that can run into hundreds of dollars for an international flight.

The exception: Some airline programs will let you upgrade for free if you've purchased a "full-fare" economy class ticket. United Airlines, part of the Star Alliance, has shifted its upgrade policy to allow miles-only upgrades to a wider range of economy-class tickets and reduced the mileage required when you do have a co-pay.

On American, elite fliers may qualify for free upgrades, but that works only in the continental United States, and passengers with a higher status than you have claim first rights on those seats.

Countermeasures: Stick with a single mileage program and try to rack up enough miles to keep elite status, which often will give you free confirmed access to "preferred" seats - those on aisles and bulkheads. This works only on the airline whose program you've joined - not its partners. And keep an eye open for deals; airlines do sometimes offer "sales" on business-class tickets that are far less expensive than usual in terms of money and/or miles.

-Mileage inflation: With car rentals, credit cards and hotel stays that can earn you miles, it's perhaps no wonder that some programs might be charging more miles for your free flights. But look at the award charts, and that's not necessarily true. (We say "necessarily" because you never know how many seats are actually available for those entry-level awards, or if they are ever available on the flight you want.)

Still, just last week, I booked a round-trip ticket to Moscow this spring for 40,000 miles via American's site on partner Air Berlin. On Delta, flights to Europe start at 30,000 miles each way but can go as high as 65,000 miles each way, thanks to its three-tiered system based on availability. American also offers a two-tiered system of "MileSaver Awards" limited by availability and "Anytime Awards" that require more miles but eliminate black-out periods; anytime awards are not available on partner flights. The plus to this system is that you can actually use your miles to get flights on your preferred dates - but it may cost you more miles.

In addition, American has introduced Dynamic Awards, available only to program members who live in the United States, that are based on the actual fare of the flight you're seeking at the time of booking - the same system used by Capital One's "anytime" miles. Theoretically the Dynamic Awards should require fewer miles, but on the flight I checked - Miami to Portland, Ore. - a MileSaver Award was available for 12,500 miles each way on the mid-March dates I chose, while a Dynamic Aware would have required 20,000 miles each way.

Countermeasures: Fly in the shoulder season, when mileage requirements are lower and seats are more readily available. If you have the option of waiting to within 14 days of travel, you may snag a seat anyway, as airlines do sometimes make additional seats available close to the date of travel on flights that aren't heavily booked.

-New ways to use miles: The best value for your miles, hands down, is a free air ticket that would cost you thousands of dollars if you had to buy it. But there are, literally, dozens of other ways to use your miles that include magazines, newspapers, dinners and charity contributions.

When it comes to using them for travel, miles from most airlines and those earned on American Express can be used for hotel rooms, vacation packages and car rentals. American, United and Delta programs all now offer "auction" sites. American's offers "once in a lifetime" experiences, such as a weekend at the Country Music Awards in Las Vegas that includes air, hotel and seats for two people; at last check, the bid was 400,000-plus miles. Delta auctions include specialty experiences and resort stays. United's offers hotels via an opaque site powered by Hotwire, where you can a specific number of miles for a hotel in a certain area but can't see the hotel name until after you close the deal.

In addition, it is possible to sell your miles for cash. The airline programs prohibit it, but it is legal. You can check their value at dozens of online sites, including FirstClassFrequentFlier.com

Airline mergers: With pending American-US Airways a virtual certainty, the question if obvious: What happens to your miles?

Rick Seaney of Farecompare.com thinks they will have even greater value, because you'll be able to use them to go more places. "If the United and Delta mergers are any indication - the merged airline will be very sensitive to business travelers and their beloved miles and perks - at least in the short term," he wrote via email.

As for my group cruise to Rome, we decided the number of miles and co-pays required were more than we wanted to part with. We decided instead to visit several national parks this fall and will buy air tickets for a few hundred dollars. But we're planning early for next year's group cruise, so we can snag that frequent flier ticket early.

---

USING FREQUENT FLYER MILES

Jane's mileage strategy:

-Book as far ahead as possible. Seats are released 330 days out.

-Look first on the website, but bear in mind not every partner's seats will be visible; while United has 30 partners hooked to its online awards system, American currently has only six.

-Call the airline when you've got plenty of time to chat up the award agent. If the agent isn't into a serious effort, call back until you get one who views award tickets as a puzzle. You may have to pay a small fee for using the agent, but it can be worth it.

-Try to keep elite frequent flier status on your airline of choice. This can be an entire art in itself, as only miles flown count toward elite status.

-Even if they don't count toward elite status, more miles more benefits. Use credit cards that earn miles on your preferred airline; stay at hotels and book rental cars that earn miles on your airline of choice.

-And yes, try to hoard your miles on a single airline. Make it one that goes the places you fly most often and that has a strong network of partners that serve destinations you'd like to visit.

-Seats to European cruise ports book quickly in summer. Try booking a free ticket to another city that's easily accessible by train or a discount airline. And run the match on those cruise lines' air-included deals, which can save serious dollars in high season.

-Want to use the miles to upgrade? Consider the cost of miles, co-pays and the initial cost of your ticket before you act. It may end up costing more to upgrade a cheap economy ticket than it would to buy a higher-priced ticket that allows upgrades with miles only.

-Most airline mileage programs will let you buy additional miles for a fee; some will let you transfer miles from one account to another. Check the math carefully before you press the "go" button.

Resources:

-Frequentflier.com

-Smartertravel.com

-Farebuzz.com (for good deals on business class tickets)

---

MORE INFORMATION

Best airline award programs:

IdeaWorksCompany, a consultant on travel loyalty programs, ranks airline programs for ease in booking entry-level award tickets in the annual Switchfly Reward Seat Availability Survey. In 2012, it ranked Southwest Airlines and Air Berlin as tied in first place. British Airways, United Airlines and AirTran were noted for most improved programs. American ranked 19th, dropping by the highest percentage of any airline. The survey was based on ease of booking award flights for October 2012 during March 2012.

Effective April 25, new changes to federal guidelines will allow passengers to carry knives with blades that are 2.36 inches or smaller and less than 1/2 inch wide. The TSA will also allow passengers to carry on some sporting equipment previously banned. Check out what is and is not allowed staring...

The Transportation Security Administration has taken to Instagram to give the public a behind-the-scenes look at its menagerie of confiscated items including guns, grenades and a slew of other weapons you wouldn’t want to mess with.

British Airways received its first Airbus A380, the world's largest commercial passenger aircraft, in July and began flying it between LAX and Heathrow on Sept. 24. Now ten airlines operate the superjumbo jet, including Thai Airways, Malaysia Airlines, Korean Air, Lufthansa, Air France, Emirates,...